Process for preparing proteinaceous food from dried brewers&#39; grains



Oct. 12, 1954 1, A, slEFKER ETAL PROCESS FOR PREPARING PROTEINACEOUS FOOD FROM DRIED BREWERS GRAINs Filed June 28, -1950 rNvENToRs;

JOSEPH A. SlEl-'KER JEROME F. BRASCH AT TORNEYS` Patented Oct. 12, 1954 PROCESS FOR PREPAR FOOD FROM DRIED Joseph A. Siefker, St. Louis, and Jerome F. Brasch, Clayton, Mo., assignors to Anheuser-Busch, Inc., St. Louis, Mo., a corporation of Missouri Application June 28, 1950, Serial No. 170,820

6 Claims.

'Ihis invention relates to a process for producing from dried brewers grains a series of products varying in protein content from a practical maximum of about 60% to a minimum of about 30%, and any or all products within these limits, and relates particularly to a product having about 45% protein (total nitrogen 6.25). The invention also relates to the products made by this process.

It is well known that the high fiber content of dried brewers grains limits its value as a feed, restricting its use as a feed for animals that can tolerate a high fiber content in their feed. Similarly, it is agreed that if the .fiber content could be reduced, dried brewers grains might serve as a high grade feed or feed supplement for, say, dogs, chicks, pigs, etc., and under favorable circumstances when the fiber content has been drastically reduced it might serve as a low fiber protein concentrate for use in human nutrition, In our new process such drastic reduction of the liber content, and concomitant enrichment of protein content has been attained, and thus makes available a useful and hitherto unattainable high protein concentrate from dried brewers grains. In the same process it may be .desirable not to reduce the ber content so drastically, thereby enriching the protein ccntent to a lesser extent, thus providing a concentr-ate which though no longer desir-able for human nutrition may still serve adequately in the diets of animals that cannot tolerate the u-nprocessed grains.

The principal object of the present invention is to detach the high protein meat portion of dried brewers grains from the husk or chaff portion thereof, and separate the two portions wholly or partially.

Another object is to produce as an article of commerce avaluable f ood product, having a biological va-lue of 87 to 88% of casein plus or minus 5% and a protein eniciency of about 1.6, which compares favorably in `these respects vwith the best cereal proteins known, thereby providing a valuable commercial food product Separated from dried brewers grains without materially decreasing the commercial value of the residue,

"Still `another object of this invention is to produce new high protein food for chickens and dogs, comparing favorably in many respects with ING PROTEINACEOUS BREWERS GRAINS the best cereal proteins known, from dried brew-- ers grains whose average protein content is too low and fiber content too high for these types of food.

This invention is embodied in a process comprising detaching the meat portion of dried brewers grains from the chaff portion thereof and separating the two detached portions, land in the products obtained therefrom.

These and other objects and advantages will become apparent hereinafter,

The invention further consists in the process hereinafter described and claimed, and in the products produced by said process. In the accompanying drawing which forms part of this specication,

Fig. 1 is a typical enlarged particle of dried brewers grains, and

Fig. 2l is a diagrammatic view showing the steps of a simplified form of this process.

Brewers dried grains result from the brewing operation in the process for making beer in the following general way. Malt, which is barley that has been steeped and allowed to germinate and which is subsequently dried, is coarsely ground and suspended in water to form What is called a mash and then heated according to a predetermined schedule to a maximum of about C'. During this heating period the diastatic enzymes in the malt solubilize the starch in the malt as well as the starch in other cereals that may have been added and which are referred to as adjuncts, leaving behind in the undissolved state most of the protein, husks and fatty material of the malt and adjuncts. This undissolved material is removed, washed free of ,soluble matter, dewatered and dried in appropriate drying equipment. The dried product so obtained is referred to .as dried brewers grains, a representative particle of which is shown enlarged in Fig. 1 of the drawings.

In this process brewers dried grains as received are directed into and through a suitable mill to detach the chaff portion or husks from the concentrated protein and fatty material 2 herein rsometimes referred to as the meat por.- tion, without appreciably reducing the particle size of the husks, thus facilitating the separation of the husks from the protein and fat portion in subsequent operations. This subsequent 3 classification or separation is effected either by a screening operation or on an air flotation table or by a combination of both operations. 1t is understood that separation of the protein from the brous material is not complete. In general three fractions are obtained. One fraction, the meat portion, constituting between 'l' and 20% of the total, is rich in protein and fat and low in fiber; another fraction, the husk, is relatively free from protein and high in fiber; and a large fraction contains protein in nearhT the same proportion as initially.

This process may therefore be broken down into the following steps:

Preparation of the grains This will usually include either iiaking, which means flattening the grains, preferably by smooth or corrugated rolls, so that they will have a larger surface area, or extra drying. Whether either is necessary depends mainly on the condition of the grains as received. This step may be eliminated by making certain changes in a subsequent operation; for example, the effect of varying moisture contents of the grains may be compensated for by using a different size screen in the classification operation.

Detachment of the proteinaceous material from. the chaff For this step a process is required in which enough action is used to loosen the proteinaceous material from the chaff, but the action must not be so strong nor of such a nature as to break D up the chaff. It has been found unexpectedly that an impact type mill 3 serves very well for this purpose, although there may be other types of mills which may serve satisfactorily. The nature of the impact surface li, the speed of the mill, the moisture content, the gap between rotor and liner, the rate of feed to the mill and other physical conditions play a role in achieving the desired final product. An impact mill with a l inch corrugated liner or impact surface 4 with corrugations sloping to the right from vertical and a rotor 5 of 14% inches operating at 3500 R. P. M. in the direction opposite to that recommended by the manufacturer, that is, clockwise as viewed from above, gives satisfactory results. mill the yield of the desired product is inversely a function of the moisture in the grains, and that flaking prior to milling tends to increase the yield. It has also been found that the yield of the desired product is a function of the rate of feed of the grains to the mill.

Classification of the high protein fraction from the chaj and middhng fractions Centrifugal air separation, air flotation, screening, or any combination of these operations may be employed for physically separating the meat from the cha'.

The high protein product derived from brewers dried` grains in the manner described comprises 7% to 20% of the brewers dried grains processed, and contains approximately 45% protein, 8% to 10% fat, has a biological value of 8'? to 88% of casein plus or minus 5% and a protein efficiency of about 1.6, and will maintain adult rats when no other protein is included in their diet. This product represents a practical and useful composition. High protein products containing approximately 60% protein have It has been found that with a given aceite() 4 been obtained with this process but the yield is lower.

The following chemical analysis of the proteinaceous or meat portion of the dried brewers grain is typical:

Protein At least 45%. Ash 3.0%. Moisture 6-10%. Crude fiber 56%.

Fat 8-10%. Nitrogen-free extract 33-26%. Carbohydrate 32-38%.

As examples of how our products are obtained, we set down the following three descriptions of our process:

Example 1.-Dried brewers grains as received containing about 5 to 10% moisture and about 27-28% protein (total nitrogen 6.25, as is basis) were fed into an impact mill of the type described and which is known in the trade as an Entoleter. Dried brewers grains containing 7% moisture and 27.7% protein were fed into the impact mill at a rate of 360 pounds per hour. The grains from this mill were then fed at a rate of 250 pounds per hour to a gyra-Whip type sifter containing four mesh screens having openings of .0055 inch. These screens each were one square foot in area and were used in series so that the grains which did not pass through the top screen were resifted on the second screen and so forth. The yield of the -100 mesh fraction was 11.4% and the protein content (total nitrogen 6.25, as is basis) was 45.2%. The yield of the +100 mesh fraction was 88.6% and its protein content was 25.5%, which is suitable for feed in a mixed dairy cattle ration.

Example 2.-Dried brewers grains as received containing about 5 to 10% moisture and about 27 to 28% protein were fed into the impact mill hereinbefore described at a rate of 360 pounds per hour. The grist was then subjected to several particle size separations by screening, which may be combined into one operation, and all but the finest fraction was processed on an air table` The purpose of the air table was to separate the higher proteinaceous material from the higher chaff material by virtue of their differences in specific gravity, the higher proteinaceous material being heavier.

The grist from the mill was fed at a rate of 250 pounds per hour to a gyra-whip type sifter containing four 100 mesh screens having openings of `0055 inch. These screens each were one square foot in area and were used in series so that the grains which did not pass through the top screen were resifted on the second screen, and so forth. The yield of the -100 mesh fraction was 11.4% and the protein content was 45.2%. The yield of the +100 mesh fraction was 88.6%. When the +100 mesh fraction was resifted on the same gyro-rotary sifter described above using two 40 mesh screens having openings of .0165 inch in series over two 20 mesh screens having openings of .0360 inch in series, three fractions were obtained: namely, +20 mesh, 20+40 mesh, and -40+l00 mesh. The yields, based on the original product, of these three fractions are 38.2%, 29.0% and 21.4%, respectively. The 40+100 mesh fraction was then processed on an air table which comprises a vibrating table having both a: lateral and end raise. Air is blown through a fine mesh bed so that when the product to be separated is fed to the low end of the table the action is such that the various components sepavaaai-,ispo

rate and the heavy fractions vibrate to'thefar end of the table. By carefully adjusting the air now, vibrating speed, lateral and end anglesfrate of feed and other physicalcharacteristics, the best separation can be observed Visually. vThe yield of material having a `protein content of 45.0%' lor more was 6.6%. If the remaining fractions were combined, the protein content would be 23.9%, which is considerably lower than the original 27.7% of dried brewers grains. In order to raise the protein of the remaining-feed 'fraction from 23.9 to 27.7%, the mesh fraction was procesed on an air table of the type previously described. Avfraction -was separated on the light end of the table having a low protein i content of 6.5% with a yield of 14.6%. Thus, we obtained from these processes three products in yields of 18.0%, 67.4% and 14.6% with protein contents of 45.1%, 27.7% and 6.5%, respectively. It can be seen from this example that use of the air table improved the yield of the 45.0% protein fraction from 11.4% as found in Example 1 to 18.0% and also permitted the removal of a very low protein and very high ber fraction which has little feed value, so that the remainder of the grains have essentially the same feed value as the original starting material.

Example .3k-Dried brewers grains as received containing about 5 to 10% moisture and about 27 to 28% protein were fed into the impact mill hereinbefore described at a rate of 360 pounds per hour. The grist was subjected to several particle size separations by screening, which may be combined into one operation, and all but the nest fraction was processed on an air table. The

purpose of the air table was to separate the higher proteinaceous material from the higher chaff material by virtue of their differences in specific gravity, the higher proteinaceous material being heavier. The grist from the mill was fed to a vibrating single deck sifter with a 100 mesh screen having an opening of .0059 inch. The yield of the 100 mesh fraction was 4.5% and the protein content thereof was 47.0%. When the +100 mesh fraction was resifted on the same vibrating single deck sifter using a 40 mesh screen having an opening of .0164 inch and in a subsequent operation using a 20 mesh screen having an opening of .0331 inch, three fractions were obtained: namely, +20 mesh, 20-+40 mesh, and 40+100 mesh. The yields of these three fractions, based on the original product, were 34.0%, 33.0% and 28.5%, respectively. These three fractions were combined in such a' manner as to produce four products: namely, a high protein product (46.5%), an intermediate protein product (35.7%) suitable for special feeds where a higher protein and lower fiber are required than for cattle feed, a cattle feed product with the same protein content as the original grains, and a low protein (7.3%) high fiber (27%) product. The yields on these products were 11.0 21.1%, 50.2% and 17.7%, respectively.

The details of this classification are hereinafter described. The +20 mesh fraction was passed over the air table and a light fraction in yield of 13.9% (based on original grains) having a protein content of 6.5 was separated. The remainder of the grains from this air tabling was combined with subsequent fractions to form the cattle feed fraction. The +20-40 mesh fraction was passed over the air table and three products were separated: namely, a light fraction in yield of 3.8% having a protein content of 8.8%, a heavy fraction in yield of 12.5% with'a protein content 'of 36.2%, and a middlingfraction in yield of 16.7%. The light fraction was combined with the light fraction from the +20mesh air tabling to form the low protein product.. .The heavy'fraction was combined with a subsequent fraction` to form the intermediate protein product. The middling fraction was combined with other fractions to form the cattle feed fraction. The 40+100 mesh fraction was passed over the air table and three fractions were separated: namely, a light fraction in'yield of 18.4%, a heavy fraction in yield of 6.5% with a protein content of 46.8%, and a middling fraction in yield of 8.6%, with 'a protein content of 34.6%. The light fraction was combined with other fractions to form the cattle feed, the heavy fraction was combined with the mesh fraction from the original screening to form the high protein product, and the middling fraction was combined with a previously mentioned fraction to form the intermediate protein product.

It is to be noted that the process is versatilethat by varying the operating conditions, the yields or the protein contents of the several products may be easily changed.

While the above examples are clear and precise descriptions of several representative processes embodying our invention, it is to be understood that we do not wish to be lmiited to the conditions of the examples except as defined in the claims. We fully realize that by varying any of the operating conditions or state of the grains before or during processing, larger yields or higher protein concentrations, or different products are possible.

As hereinbefore indicated, if 100 units of dried brewers grains are subjected to this process, approximately 7 to 20 units will be broken down substantially into a high protein meat portion having a 45% protein content and 13 to 17 units into a chaff portion having a 6.5% protein content. The high protein meat portion can be used as a high protein food and can even be used for human consumption. The low protein chaff portion could possibly be used for jected to a complete classification, then intermediate products containing 35 to 40% protein can be obtained. The 40% protein products are are useful for dog food and the 35% protein products are useful as a chicken feed.

What we claim is:

1. A process of preparing a high proteinaceous food product from dried brewers grains which material without materially breaking up the husks, and separating the chaff portion.

2. The process according to claim l wherein the chaff portion is separated by screening.

3. The process according to claim 1 wherein the chaff portion is separated by air flotation.

4. The process according to claim 1 wherein the chafic portion is separated by centrifugal air separation.

5. The process according to claim 1 wherein the milling action is carried out by an impact mill.

6. The process of preparing a finely divided low fiber high protein content supplement suitable for use in human nutrition, derived from dried brewers grains, which comprises the steps of subjecting the grains to the action of an impact mill to effect detachment of the husks from the proteinaceous material, controlling the action of the mill to eiect such detachment without materially breaking up the husks, and iinaliy separating the mixture of cha and proteinaceous material by subjecting the mixture to successive screenings to obtain a flour having a fneness of the order of 10U mesh` References Cited in the file of this patent p UNITED STATES PATENTS Number Name Date Schaefer Oct. 21, 1879 15 8 Number Name Date 330,184 Zimmer Nov. 10, 1885 949,581 Kubessa Feb. 15, 1910 1,975,731 Parsons Oct. 2, 1934 2,236,806 Sutton Apr. 1, 1941 2,355,028 Musher Aug. 1, 1944 2,464,212 Carter Mar. 15, 1949 OTHER REFERENCES Hopkins and Krause: Biochemistry Applied to Malting and Brewing, George Allen and Unwin Ltd., London, 1937, pp. 244-45.

Prescott and Dunn: Industrial Microbiology, McGraw-Hill, N. Y., pp. 51, 97, 98, and 100. 

6. THE PROCESS OF PREPARING A FINELY DIVIDED LOW FIBER HIGH PROTEIN CONTENT SUPPLEMENT SUITABLE FOR USE IN HUMAN NUTRITION, DERIVED FROM DRIED BREWERS'' GRAINS, WHICH COMPRISES THE STEPS OF SUBJECTING THE GRAINS TO THE ACTION OF AN IMPACT MILL TO EFFECT DETACHMENT OF THE HUSKS FROM THE PROTEINACEOUS MATERIAL, CONTROLLING THE ACTION OF THE MILL TO EFFECT SUCH DETACHMENT WITHOUT MATERIALLY BREAKING UP THE HUSKS, AND FINALLY SEPARATING THE MIXTURE OF CHAFF AND PROTEINACEOUS MATERIAL BY SUBJECTING THE MIXTURE TO SUCCESSIVE SCREENINGS TO OBTAIN A FLOUR HAVIN A FINENESS OF THE ORDER OF 100 MESH. 